A variety of formulations for human use are stored in the form of a dry particulate matter (powder) and are mixed with a liquid shortly before use to form a true solution or a dispersion. This is the case, for example, with various nutritive formulas, including maternal milk substitute formulas (baby formula), adult feeding formulas such as dietetic powders and a variety of drugs, e.g., antibiotics. The shelf life of such mixed liquid formulations is limited, and this dictates the need to prepare them only shortly before use. The limited shelf life of the mixed formulation is the result of a loss of activity of an active ingredient in the formula, for example, loss of activity due to accelerated oxidation and/or hydrolysis once the ingredient is mixed with a liquid, etc. In addition, in many cases, the mixed formulation can be more susceptible to micro-organism contamination.
In some applications, for example, formula for newborn babies and various drugs including antibiotics, it is important that a correct amount (weight and/or volume) of the dry particulate material be admixed with a correct amount (weight and/or volume) of the liquid when preparing the resulting formula. Too much or too little of any one of the required components alters the ratio and changes the resulting formulation which may need to be within close tolerances to have the appropriate effect. For example, in the case of baby formula if there is not enough dry formula the mixed liquid formulation will be diluted in which case the baby or infant will be undernourished, or if there is too much dry formula the mixed liquid formulation will be too concentrated which may give rise to digestive problems and vomiting.
In addition, in some applications it may be necessary that the filling, storing and mixing of the two compartments be performed under hygienic and in some cases sterile conditions and that the two components be of appropriate sterility and quality.
The preparation of baby formula in the home and hospitals is typically accomplished by providing cleaned and sterilized bottles and nipples, measuring a quantity of the powdered (dry particulate) material from a canister and placing it in the previously cleaned and sterilized bottle to which an appropriate measured amount of water (generally tap water), saline solution or milk is added. The nipple is then attached and the two constituents or components are then agitated to form the mixed liquid formula. A variety of drugs, for example, antibiotics are prepared in a similar manner by the pharmacist or the end user.
In applications where a formula prepared by mixing two constituents has a short shelf-life or where the quantities, quality or sterility of the constituents is an important consideration in the preparation of the formula, a single container which could separately store the two constituents until the mixed formula is to be dispensed, permit the two constituents to be mixed in the container and permit the mixed formula to be dispensed from the container would be useful. In some such applications it may further be desirable that the container be pre-packaged and yet further desirable that it be configured and adapted for a single use by the end user and even more desirable that the container be unusable after the single use. Such storage and dispensing containers would offer convenience, safety and potential savings to the end user.
First, a pre-packaged two-compartment storage and dispensing container offers the convenience of having both constituent parts of a mixed formulation supplied in the correct amounts in a single easy to use container that is always ready to be mixed. In this manner, a traveler may take along as many pre-packaged containers as desired and mix the formula for use at any time, without having to measure the two or more constituents, or worry about forgetting or obtaining one of the constituents of the formula while traveling. Such a pre-packaged container, filled and packaged under the appropriate conditions, separately storing the constituent elements of a formula in a ready to mix manner, and adaptable to mix and dispense the resulting formulation provides a complete system for the end user.
Second, single use two-compartment storage and dispensing containers offer the safety of being packaged in a manufacturing plant where the sterility of the environment and the quality and sterility of each of the constituents and mixed formula can be controlled. In addition, the quantity of each of the two separate components can be controlled through precise measurement if prepackaged in a single use container in a manufacturing facility.
Containers having separate compartments for storing two components, e.g., one being a dry particulate substance and the other being a liquid, both of which are mixed together prior to use, are known. Such two-compartment containers typically employ a breakable or displaceable partition between the two compartments. The partition is then either broken or displaced, as the case may be, to allow mixing.
A major problem with known two-container designs is the complexity of the assembly, filling and packaging process. This complexity results from the need to assemble an internal partition, which may in itself be designed to be fragile or easily displaceable, through the typically restricted access of the container opening. There is therefore a need for two-compartment containers which are easily manufactured and simplify the assembly, filling and packaging process while offering easy and reliable operation.